U.S. patent number 6,045,687 [Application Number 08/955,626] was granted by the patent office on 2000-04-04 for catalyst containing at least two dealuminated y zeolites and a conventional hydroconversion process for petroleum cuts using this catalyst.
This patent grant is currently assigned to Institut Francais du Petrole. Invention is credited to Eric Benazzi, Nathalie George-Marchal, Slavik Kasztelan, Samuel Mignard.
United States Patent |
6,045,687 |
Mignard , et al. |
April 4, 2000 |
Catalyst containing at least two dealuminated Y zeolites and a
conventional hydroconversion process for petroleum cuts using this
catalyst
Abstract
A catalyst support comprising at least one matrix, at least one
Y zeolite with a lattice parameter which is in the range 24.15
.ANG. to 24.38 .ANG. (1 nm=10 .ANG.) and at least one Y zeolite
with a lattice parameter of more than 24.38 .ANG. and less than or
equal to 24.51 .ANG.. The invention also concerns a catalyst
comprising said support and at least one hydro-dehydrogenating
element, and a conventional hydroconversion process for petroleum
cuts using said catalyst.
Inventors: |
Mignard; Samuel (Chatou,
FR), George-Marchal; Nathalie (Paris, FR),
Benazzi; Eric (Chatou, FR), Kasztelan; Slavik
(Rueil Malmaison, FR) |
Assignee: |
Institut Francais du Petrole
(FR)
|
Family
ID: |
9496973 |
Appl.
No.: |
08/955,626 |
Filed: |
October 22, 1997 |
Foreign Application Priority Data
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Oct 22, 1996 [FR] |
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96-12957 |
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Current U.S.
Class: |
208/111.3;
208/111.35; 208/109; 502/64; 208/111.01; 502/79; 502/67 |
Current CPC
Class: |
C10G
47/16 (20130101); B01J 29/084 (20130101); C10G
47/20 (20130101); B01J 2229/42 (20130101); B01J
2229/26 (20130101) |
Current International
Class: |
B01J
29/08 (20060101); C10G 47/16 (20060101); C10G
47/20 (20060101); C10G 47/00 (20060101); B01J
29/00 (20060101); C10G 047/16 () |
Field of
Search: |
;502/64,67,79
;208/111.3,109,111.01,111.35 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0 287 718 |
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Oct 1988 |
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EP |
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2 119 636 |
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Aug 1972 |
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FR |
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2 348 265 |
|
Nov 1977 |
|
FR |
|
Primary Examiner: Dunn; Tom
Attorney, Agent or Firm: Millen, White, Zelano &
Branigan, P.C.
Claims
We claim:
1. A support containing at least one matrix and at least one Y
zeolite (Y1) with a lattice parameter of 24.15 .ANG. to 24.38 .ANG.
and at least one Y zeolite (Y2) with a lattice parameter of more
than 24.38 .ANG. and less than or equal to 24.51 .ANG..
2. A support according to claim 1, in which the weight content of
the matrix in the support is 20% to 98%.
3. A support according to claim 1, in which the matrix is alumina,
silica, magnesia, titanium oxide, zirconium oxide an aluminum
phosphate, a titanium phosphate, a zirconium phosphate, boron
oxide, clay, or a mixture thereof.
4. A support according to claim 1, in which the Y1/Y2 weight ratio
is in the range 0.1 to 100.
5. A support according to claim 1, wherein (Y1) has a lattice
parameter of 24.28 to 24.38 and (Y2) has a lattice parameter of
24.42 to 24.51.
6. A support according to claim 1, wherein (Y1) has a lattice
parameter of 24.15 to 24.28 and (Y2) has a lattice parameter of
24.42 to 24.51.
7. A support according to claim 1, wherein (Y1) has a lattice
parameter of 24.28 and (Y2) has a lattice parameter of 24.42.
8. A support according to claim 1, wherein (Y1) has a pore
distribution in which 1-20% of the pore volume is pores with a
diameter of 20 .ANG. to 80 .ANG., and a major portion of remaining
pore volume is pores with a diameter less than 20 .ANG..
9. A catalyst comprising at least one matrix, at least one Y
zeolite (Y1) with a lattice parameter of 24.15 .ANG. to 24.38 .ANG.
and at least one Y zeolite (Y2) with a lattice parameter of more
than 24.38 .ANG. and less than or equal to 24.51 .ANG., and at
least one hydrogenating or dehydrogenating element.
10. A catalyst according to claim 9, in which the matrix is
alumina, silica, magnesia, titanium oxide, zirconium oxide an
aluminum phosphate, a titanium phosphate, a zirconium phosphate,
boron oxide, clay, or a mixture thereof.
11. A catalyst according to claim 9, in which the hydrogenating or
dehydrogenating element is an element from group VIII or group VI
of the periodic table.
12. A catalyst according to claim 9, in which the content of the
matrix in the support is 20% to 98% by weight.
13. A catalyst according to claim 9, having a Y1/Y2 weight ratio of
0.1 to 100.
14. A catalyst according to claim 9, having a Y1/Y2 weight ratio is
of 0.3 to 30.
15. A catalyst according to claim 9, containing 1% to 40% by weight
of hydrogenating elements based on oxides.
16. A catalyst according to claim 9, further containing 0.1% to 15%
by weight of diphosphorous pentoxide.
17. A process for the preparation of a catalyst according to claim
9, comprising mixing zeolites with the matrix, introducing at least
a portion of hydrogenating elements, forming and calcining.
18. A process for the preparation of a catalyst according to claim
17, in which hydrogenating group VII element(s) and group VI
element(s) are introduced, and the group VIII element(s) is/are
introduced after or simultaneously with introduction of the group
VI element(s).
19. A process for the preparation of a catalyst according to claim
9, comprising mixing zeolites with the matrix, forming and
calcining the support and introducing hydrogenating element(s).
20. A process for the preparation of a catalyst according to claim
9, comprising mixing the zeolites with the matrix, to obtain the
support, introducing hydrogenating element(s) and calcining.
21. A process for the conversion of a petroleum cut in which the
cut is brought into contact with a catalyst according to claim 9,
at a temperature of at least 230.degree. C., a pressure of at least
8 MPa, in the presence of a quantity of hydrogen of at least 100
Nl/l of feed, with an hourly space velocity of 0.15 to 10
h.sup.-1.
22. A process according to claim 21, wherein the catalyst is a
sulphurized catalyst.
23. A process according to claim 21, in which the cut has first
undergone hydrotreatment.
24. A process according to claim 23, in which the hydrotreatment
catalyst comprises a matrix selected from alumina, silica, boron
oxide, magnesia, zirconia, titanium oxide or a combination of these
oxides, and the catalyst also comprises at least one metal having a
hydro-dehydrogenating function, which is a group VI or group VIII
metal, the total concentration of oxides of said metals being 5% to
40% by weight, and the weight ratio of group VI metal oxides to
group VIII metal oxides being 1.25 to 30, and the catalyst
optionally containing at most 15% by weight of diphosphorous
pentoxide.
25. A process according to claim 21, in which hydrotreatment takes
place between 350-460.degree. C., at a pressure of 8-20 MPa, with a
quantity of hydrogen of at least 100 Nl/l of feed and an hourly
space velocity of 0.1-5 h.sup.-1.
26. A process according to claim 21, in which the cut comprises at
least 80% by volume of compounds with boiling points of at least
350.degree. C.
27. A process according to claim 21, in which the petroleum cut is
a gas oil, vacuum distillate, deasphalted residue or a hydrotreated
residue.
Description
BACKGROUND OF THE INVENTION
The present invention concerns a support comprising at least two
dealuminated Y zeolites associated with a matrix which is normally
amorphous or of low crystallinity, a catalyst containing that
support, its use in conventional hydroconversion of petroleum cuts
and a hydroconversion process using the support.
Conventional hydrocracking of heavy petroleum cuts is a process
which is very important in refining which produces, from surplus
and heavy feeds of low upgradability, lighter fractions such as
gasolines, aviation fuel and light gas oils which the refiner needs
in order to adapt his production to demand. In comparison with
catalytic cracking, catalytic hydrocracking is important for the
production of very high quality middle distillates, aviation fuels
and gas oils. In contrast, the gasoline produced has a much lower
octane number than that from catalytic cracking.
The catalysts used in conventional hydrocracking are all
bifunctional, associating an acid function with a hydrogenating
function. The acid function is provided by supports with large
surface areas (generally 150 to 800 m.sup.2.g.sup.-1) with a
superficial acidity, such as halogenated aluminas (in particular
chlorinated or fluorinated aluminas), combinations of boron oxides
and aluminium oxides, amorphous silica-aluminas and zeolites. The
hydrogenating function is provided either by one or more metals
from group Vm of the periodic table, such as iron, cobalt, nickel,
ruthenium, rhodium, palladium, osmium, iridium and platinum, or by
the association of at least one metal from group VI of the periodic
table, such as chromium, molybdenum and tungsten, and at least one
group VIII metal, preferably a non-noble metal.
The balance between the two functions, acid and hydrogenating, is
the fundamental parameter which governs the activity and
selectivity of the catalyst. A weak acid function and a strong
hydrogenating function results in catalysts of low activity which
generally work at a high temperature (390.degree. C. or more) and
at a low space velocity (HSV, expressed as the volume of feed to be
treated per unit volume of catalyst per hour, generally less than
2), but have very good selectivity for middle distillates.
Conversely, a strong acid function and a weak hydrogenating
function results in very active catalysts with, however, poor
selectivity for middle distillates. The operator's problem is thus
careful choice of each of the functions to adjust the
activity/selectivity couple of the catalyst.
Thus it is very important in hydrocracking to have great
flexibility at various levels: flexibility in the catalysts used,
which provides flexibility in the feeds to be treated and in the
products obtained. One parameter is the acidity of the catalyst
support.
The great majority of conventional catalytic hydrocracking
catalysts contain weakly acidic supports, such as amorphous
silica-aluminas. Such systems are used to produce very high quality
middle distillates and, when of very low acidity, oil stock.
Amorphous silica-aluminas form a family of low acidity supports.
Many commercial hydrocracking catalysts are constituted by
silica-alumina associated with either a group VIII metal or, as is
preferable when the quantity of heteroatomic poisons in the feed to
be treated exceeds 0.5% by weight, with an association of sulphides
of metals from groups VIB and VIII. Such systems have very good
selectivity for middle distillates and the products formed are of
high quality. The least acidic of such catalysts can also produce
lubricant stock. The disadvantage of all of these catalytic systems
based on an amorphous support is, as has already been stated, their
low activity.
SUMMARY OF THE INVENTION
The present invention overcomes these disadvantages. It provides a
support comprising at least one matrix, at least one Y zeolite, Y1,
with a lattice parameter which is in the range 24.15 .ANG. to 24.38
.ANG. (1 nm=10 .ANG.) and at least one Y zeolite, Y2, with a
lattice parameter of more than 24.38 .ANG. and less than or equal
to 24.51 .ANG.. It also provides a catalyst comprising at least the
support of the invention and at least one hydro-dehydrogenating
element.
In the remainder of the text, the lattice parameter units will be
expressed in .ANG. (1 nm=10 .ANG.).
The catalyst and support of the present invention thus comprises at
least two Y zeolites with faujasite structure ("Zeolite Molecular
Sieves: Structure, Chemistry and Uses", D. W. Breck, J. Wiley &
Sons, 1973) which can either be in the hydrogen form or in a form
which is partially exchanged with metal cations, for example with
alkaline-earth metal cations and/or cations of rare earth metals
with atomic number 57 to 71 inclusive. The first, known here as Y1,
has a lattice parameter of more than 24.15 .ANG. up to 24.38 .ANG..
The second, known here as Y2, has a lattice parameter of more than
24.38 .ANG. and less than or equal to 24.51 .ANG.. The Y1/Y2 weight
ratio, i.e., the ratio between the first and the second zeolite, is
in the range 0.1 to 100, advantageously in the range 0.1 and 80,
more advantageously in the range 0.1 to 50, preferably in the range
0.3 to 30, and more preferably in the range 0.5 to 10. The total
weight content of the matrix with respect to the support (the
support is constituted by the matrix and the totality of the Y
zeolites) is in the range 1% to 98%, advantageously in the range
20% to 98%, preferably in the range 25% to 98%, more preferably in
the range 40% to 97% and more advantageously in the range 65% to
95%.
The preferred acid zeolite Y1 is characterized by various
specifications: a lattice parameter in the range 24.15 .ANG. to
24.38 .ANG.; a framework SiO.sub.2 /Al.sub.2 O.sub.3 molar ratio,
calculated using the Fichtner-Schmittler correlation (in Cryst.
Res. Tech. 1984, 19, K1) in the range about 500 to 21; a sodium
content of less than 0.15% by weight determined on zeolite calcined
at 1100.degree. C.; a sodium ion take-up capacity C.sub.Na,
expressed in grams of Na per 100 grams of modified, neutralized
then calcined zeolite, of more than about 0.85; a specific surface
area, determined using the BET method, of more than about 400
m.sup.2 /g, preferably more than 550 m.sup.2 /g; a water vapour
adsorption capacity at 25.degree. C. for a partial pressure of 2.6
torrs (i.e., 34.6 MPa) of more than about 6%, and a pore
distribution wherein between 1% and 20%, preferably between 3% and
15%, of the pore volume is contained in pores with a diameter
between 20 .ANG. and 80 .ANG., the major part of the remainder of
the pore volume being contained in pores with a diameter of less
than 20 .ANG..
The other preferred acid zeolite Y2 is characterized by various
specifications: a lattice parameter in the range 24.38 .ANG. to
24.51 .ANG.; a framework SiO.sub.2 /Al.sub.2 O.sub.3 molar ratio,
calculated using the Fichtner-Schmittler correlation (in Cryst.
Res. Tech. 1984, 19, K1) of less than about 21 and greater than or
equal to 10; a sodium content of less than 0.15% by weight
determined on zeolite calcined at 1100.degree. C.; a sodium ion
take-up capacity C.sub.Na, expressed in grams of Na per 100 grams
of modified, neutralized then calcined zeolite, of more than about
0.85; a specific surface area, determined using the BET method, of
more than about 400 m.sup.2 /g, preferably more than 550 m.sup.2
/g; a water vapor adsorption capacity at 25.degree. C. for a
partial pressure of 2.6 torrs (i.e., 34.6 MPa) of more than about
6%, and a pore distribution wherein between 1% and 20%, preferably
between 3% and 15%, of the pore volume is contained in pores with a
diameter between 20 .ANG. and 80 .ANG., the major part of the
remainder of the pore volume being contained in pores with a
diameter of less than 20 .ANG..
The catalyst and support thus comprise at least these two zeolites
Y1 and Y2 but it can contain more than two provided that these
zeolites have the lattice parameters of Y1 or Y2.
Any method which can produce zeolites Y1 and Y2 having the
characteristics defined above is suitable.
The catalyst and support of the present invention also comprise at
least one matrix which is normally amorphous or of low
crystallinity selected, for example, from the group formed by
alumina, silica, magnesia, titanium oxide, zirconia, aluminium,
titanium or zirconium phosphates, clay, boron oxide and
combinations of at least two of these compounds.
The matrix is preferably selected from the group formed by silica,
alumina, magnesia, silica-alumina combinations, and silica-magnesia
combinations.
The catalyst of the present invention can be prepared using any of
the methods known to the skilled person. It is advantageously
obtained by mixing the matrix and zeolites then forming. The
hydrogenating element is introduced during mixing, or it can be
introduced after forming (preferred). Forming is followed by
calcining, the hydrogenating element being introduced before or
after calcining. In all cases, the preparation is finished by
calcining at a temperature of 250.degree. C. to 600.degree. C. One
preferred method consists of mixing Y zeolites of faujasite
structural type in a wet alumina gel for several tens of minutes,
then passing the paste obtained through a die to form extrudates
with a preferred diameter of between 0.4 mm and 4 mm.
The catalyst also includes a hydrogenating function. The
hydro-dehydrogenating function is provided by at least one group
VIII metal or a compound of a group VIII metal, in particular
nickel and cobalt. A combination of at least one metal or compound
of a metal from group VI of the periodic table (in particular
molybdenum or tungsten) and at least one metal or compound of a
metal from group VIII in the periodic table, preferably a non noble
metal (in particular cobalt or nickel), can be used. The
hydrogenating function itself as defined above can be introduced
into the catalyst at various stages of the preparation and in
various ways.
It can be introduced only in part (for example for associations of
oxides of group VI and group VIII metals) or in total when mixing
the two zeolite types with the gel of the oxide selected as the
matrix, the remainder of the hydrogenating element(s) then being
introduced after mixing, and more generally after calcining. The
group VIII metal is preferably introduced simultaneously with or
after the group VI metal, whatever the method of introduction. It
can be introduced in one or more ion exchange operations on the
calcined support constituted by zeolites dispersed in the selected
matrix, using solutions containing precursor salts of the selected
metals when these are from group VIII. It can be introduced using
one or more operations to impregnate the formed and calcined
support with a solution of precursors of oxides of group VIII
metals (in particular cobalt and nickel) when the precursors of
oxides of metals from group VI (in particular molybdenum or
tungsten) have been introduced on mixing the support. Finally, it
can be introduced by one or more operations to impregnate the
calcined support, constituted by zeolites and the matrix, with
solutions containing precursors of oxides of group VI and/or group
VIII metals, the precursors of oxides of group VIII metals
preferably being introduced after those of group VI or at the same
time as the latter.
When the elements are introduced by impregnating several times with
the corresponding precursor salts, intermediate calcining of the
catalyst must be carried out at a temperature which is in the range
250.degree. C. to 600.degree. C.
The total concentration of oxides of group VIII and VI metals is in
the range 1% to 40% by weight of the catalyst obtained after
calcining, preferably in the range 3% to 30% and advantageously in
the range 8% to 40%, more advantageously 10% to 40% and even more
advantageously, 10% to 30%. The ratio of group VI metal(s) to group
VIII metal(s) is generally in the range 20 to 1.25, preferably in
the range 10 to 2, expressed by weight as the metal oxides. The
catalyst can also contain phosphorous. The concentration of
phosphorous oxide (P.sub.2 O.sub.5) is generally at most 15%, in
the range 0.1% to 15%, preferably in the range 0.15% to 10% by
weight.
Impregnation of molybdenum can be facilitated by adding phosphoric
acid to the molybdenum salt solutions.
The catalysts obtained, in the form of oxides, can optionally be at
least partially changed into the metallic or sulphide form.
They are charged into the reactor and used for hydrocracking, in
particular of heavy cuts. Activity is improved over the prior art,
and the selectivity for the production of very good quality middle
distillates is also improved.
The petroleum cuts to be treated have boiling points of more than
100.degree. C. Examples are kerosines, gas oils, vacuum
distillates, deasphalted or hydrotreated residues, or equivalents
thereof. The feeds, which are highly charged with N and S, are
preferably hydrotreated first. The heavy cuts are preferably
constituted by at least 80% by volume of compounds with boiling
points of at least 350.degree. C., preferably between 350.degree.
C. and 580.degree. C. (i.e., corresponding to compounds containing
at least 15 to 20 carbon atoms). They generally contain heteroatoms
such as sulphur and nitrogen. The nitrogen content is usually in
the range 1 to 5000 ppm by weight and the sulphur content is in the
range 0.01% to 5% by weight. Hydrocracking conditions, such as
temperature, pressure, hydrogen recycle ratio, and hourly space
velocity, can vary depending on the nature of the feed, the quality
of the desired products, and the facilities available to the
refiner.
When hydrotreatment is necessary, the petroleum cut conversion
process is carried out in two steps, the catalysts of the invention
being used in the second step.
Catalyst 1 of the first hydrotreatment step comprises a matrix,
preferably based on alumina, and preferably containing no zeolite,
and at least one metal with a hydro-dehydrogenating function. This
matrix can also be constituted by, or include, silica,
silica-alumina, boron oxide, magnesia, zirconia, titanium oxide or
a combination of these oxides. The hydro-dehydrogenating function
is provided by at least one metal or compound of a metal from group
VIII of the periodic table such as nickel or cobalt. A combination
of at least one metal or compound of a metal from group VI of the
periodic table (in particular molybdenum or tungsten) and at least
one metal or compound of a metal from group VIII (in particular
cobalt or nickel) from the periodic table can be used. The total
concentration of oxides of group VI and group VIII metals is in the
range 5% to 40% by weight, preferably in the range 7% to 30% by
weight, and the ratio of group VI metal(s) to group VIII metal(s)
is in the range 1.25 to 20, preferably in the range 2 to 10,
expressed by weight as the metal oxides. The catalyst can also
contain phosphorous. The phosphorous content, expressed as the
concentration of diphosphorous pentoxide P.sub.2 O.sub.5, is
generally at most 15%, preferably in the range 0.1% to 15%, and
more preferably in the range 0.15% to 10% by weight.
The first step is generally carried out at a temperature of
350.degree. C. to 460.degree. C., preferably 360.degree. C. to
450.degree. C., at a total pressure of 8 to 20 MPa; preferably 8 to
15 MPa, an hourly space velocity of 0.1 to 5 h.sup.-1, preferably
0.2 to 2 h.sup.-1, and with a quantity of hydrogen of at least
100Nl/Nl of feed, preferably 260-3000 Nl/Nl of feed.
In the case of the conversion step using the catalyst of the
invention (second step), the temperatures are generally 230.degree.
C. or more, usually in the range 300.degree. C. to 430.degree. C.
The pressure is generally 8 Mpa or more. The quantity of hydrogen
is a minimum of 100 l/l of feed, usually in the range 200 to 3000
l/l of hydrogen per liter of feed. The hourly space velocity is
generally in the range 0.15 to 10 h.sup.-1.
The parameters which are important to the refiner are the activity
and selectivity towards middle distillates. Fixed targets must be
achieved under conditions which are compatible with economic
reality. Under conventional operating conditions, this type of
catalyst can produce selectivities of more than 65% for middle
distillates with boiling points in the range 150.degree. C. to
380.degree. C., with levels of conversion of more than 55% by
volume for products with a boiling point of less than 380.degree.
C. Further, this catalyst has remarkable stability under these
conditions. Finally, because of the composition of the catalyst, it
can readily be regenerated.
Surprisingly, we have been able to establish that, in accordance
with the invention, a catalyst containing at least two dealuminated
Y zeolites can produce a selectivity for middle distillates which
is substantially improved compared with prior art catalysts. The
following examples illustrate the present invention without in any
way limiting its scope.
EXAMPLES
Example 1
Production of Catalyst C1
Catalyst C1 was produced as follows: 20% by weight of a Y zeolite
with a lattice parameter of 24.42 .ANG. was used, mixed with 80% by
weight of SB3 type alumina from Condea. The mixed paste was then
extruded through a 1.4 mm diameter die. The extrudates were dried
overnight at 120.degree. C. in air then calcined at 550.degree. C.
in air. The extrudates were dry impregnated using a solution of a
mixture of ammonium heptamolybdate, nickel nitrate and
orthophosphoric acid, dried overnight at 120.degree. C. in air then
calcined in air at 550.degree. C. The concentrations of active
oxides were as follows (by weight with respect to the
catalyst):
2.6% by weight of nickel oxide NiO;
12.7% by weight of molybdenum oxide MoO.sub.3 ;
5.5% by weight of phosphorous oxide P.sub.2 O.sub.5.
Example 2
Production of Catalyst C2
Catalyst C2 was produced as follows: 20% by weight of a Y zeolite
with a lattice parameter of 24.28 .ANG. was used, mixed with 80% by
weight of SB3 type alumina from Condea. The mixed paste was then
extruded through a 1.4 mm diameter die. The extrudates were dried
overnight at 120.degree. C. in air then calcined at 550.degree. C.
in air. The extrudates were dry impregnated using a solution of a
mixture of ammonium heptamolybdate, nickel nitrate and
orthophosphoric acid, dried overnight at 120.degree. C. in air then
calcined in air at 550.degree. C. The concentrations of active
oxides were as follows (by weight with respect to the
catalyst):
2.7% by weight of nickel oxide NiO;
12.8% by weight of molybdenum oxide MoO.sub.3 ;
5.4% by weight of phosphorous oxide P.sub.2 O.sub.5.
Example 3
Production of Catalyst C3
Catalyst C3 was produced as follows: 10% by weight of a Y zeolite
with a lattice parameter of 24.42 .ANG. and 10% by weight of a Y
zeolite with a lattice parameter of 24.28 .ANG. were used, mixed
with 80% by weight of SB3 type alumina from Condea. The mixed paste
was then extruded through a 1.4 mm diameter die. The extrudates
were dried overnight at 120.degree. C. in air then calcined at
550.degree. C. in air. The extrudates were dry impregnated using a
solution of a mixture of ammonium heptamolybdate, nickel nitrate
and orthophosphoric acid, dried overnight at 120.degree. C. in air
then calcined in air at 550.degree. C. The concentrations of active
oxides were as follows (by weight with respect to the
catalyst):
2.6% by weight of nickel oxide NiO;
12.7% by weight of molybdenum oxide MoO.sub.3 ;
5.4% by weight of phosphorous oxide P.sub.2 O.sub.5.
Example 4
Comparison of C1, C2 and C3 in a High Pressure Test
The catalysts prepared as in the preceding examples were used under
hydrocracking conditions on a petroleum feed with the following
principal characteristics:
______________________________________ Initial point 277.degree. C.
10% point 381.degree. C. 50% point 482.degree. C. 90% point
531.degree. C. End point 545.degree. C. Pour point +39.degree. C.
Density (20/4) 0.919 Sulphur (% by weight) 2.46 Nitrogen (ppm by
weight) 930 ______________________________________
The catalytic test unit comprised two fixed bed reactors operating
in upflow mode. 40 ml of catalyst was introduced into each
catalyst. A first hydrotreatment step catalyst 1, HR360 sold by
Procatalyse, comprising a group VI element and a group VIII element
deposited on alumina, was introduced into the first reactor, into
which the feed was initially fed. A second step catalyst 2, i.e.,
the hydroconversion catalyst, was introduced into the second
reactor, into which the feed was finally fed. The two catalysts
underwent in-situ sulphurisation before the reaction. It should be
noted that any in-situ or ex-situ sulphurisation method would have
been suitable. Once sulphurisation had been carried out, the feed
described above could be transformed. The total pressure was 9 MPa,
the hydrogen flow rate was 1000 liters of gaseous hydrogen per
liter of feed injected, and the hourly space velocity was 1.0
h.sup.-1.
The catalytic performances were expressed as the temperature which
could produce a gross conversion of 70%, and by the gross
selectivity. These catalytic performances were measured on the
catalyst after a period of stabilisation had passed, generally at
least 48 hours.
The gross conversion, GC, is defined as: ##EQU1##
The reaction temperature was fixed so as to obtain a gross
conversion GC of 70% by weight. The following table shows the
reaction temperature and the gross selectivity for the three
catalysts.
______________________________________ T (.degree. C.) GS
______________________________________ C1 372 59 C2 396 71 C3 385
70 ______________________________________
Using a mixture of zeolites produced a very high selectivity,
higher than that of catalyst C1 and the same as that of catalyst
C2, while using a lower reaction temperature as a temperature gain
of 11.degree. C. was observed with respect to catalyst C2.
* * * * *